Reversing split-phase motor



Aug. 14, 1945. c E, SPRAGUE ET AL I 2,382,827

REVERSING SPLIT PHASE MOTOR Filed Sept. 1, 1.942 2 Sheets-Sheet l I Aug. 14, 1945.

c. E. SPRAGUE ET AL 82,827

REVERSING SPLIT PHASE MOTOR 2 Sheets-Sheet 2 Patented Aug. 14, 1945 1 OFFICE WING SPLIT-PHASE MOTOR Chester E. Sprague and Nelson M. Sprague,

Application September 1, 1942, Serial No. 456,848

4 Claims. (CL 172-279) This invention relates generally to split phase motors and particularly to an instant reversin switch therefor.

The main object of this invention is to construct an instant reversing switchfor split phase motors employing a purely mechanical means for varying the relationship of the windings instead of employing relays, transformers and other electrical elements. commonly employed in.

actuated reversing switches. 'fri e s md object is to construct a reversing switch of the class described which can be reversed without waiting for the motor to come to a full stop.

. The third object is toconstmct a switch of the class described especially adapted for use in connection with motors where instant reversing is desirable, such as on ascrew cutting lathe, elevators, and other types of equipment.

' The fourth objectv is to construct a switch of the class described whereinthe rotation of the rotor in either direction will set the switch or prepare it for the next reversing operation which is initiated by a manual operation or by an elecrated actuator such as a solenoid. -1 3m object is to construct a simple and eilicient form of switch for the p rp se stated which will require a minimum amount of material essential in other lines of industry, and which can be applied to approximately; ninety percent h s lit hase motors now n use.

vte ac omglish these and other objects in the manner set forth in the following specification as illustrated in the accompanying drawings, in

hich: 1 Fig. 1 is a diagrammatic view showing the parts in position for clockwise rotation of the motor. Fig. 2 is a view similar to Fig. 1 but showing the parts in position for a counter-clockwise rotation of the motor. v

Fig. 3 is a transverse section through the manually operated switch taken along the hue 3-3 in Fig. 4 with the cover removed.

the motor governor parts in a position of rest.

Fig. 9 is a section taken along the line 9-! in Fig. 8.

Similar numerals throughout the several views.

Referring in detail to the drawings, there is shown in dotted lines the position of the rotor ll of a motor whose shaft ll journals in the bearing I 2 which forms a part of the stationary casing ll.

Attached to the rotor lo governor frame ll whose i rockable on the pivots It.

The arms II are provided with counterweights ll which move outwardly as shown in Fig. 6 when the motor attains speed. The arms I! bear against the flange it of a slidable and the frictional switch is a common form of nturned arms It are plastic collar ll whose bell shaped end 20 is commonly employed to control the starting winding circuit by means of a switch which is replaced by our device.

Referring particularly to our invention, same will be seen to consist of two principal parts; namely, a frictionally set switch unit F, and a manually actuated switch unit M.

Frictionallv set switch unit and secured to the casing II by means of the screws 23.

The base II is provided with a circular opening 24 through which the shaft l I can pass without touching same.

On the base II are mounted arms 25 and 26 whose contact points 21 and 28 are diametrically opposite eachother.

Encircling the shaft the spring contact II and spaced therefrom is a collar 28 of insulating material on which Fig. 4 is a side elevation of the manually operated switch with the cover cut along the line Fig.8 is a viewslmilar to Fig. 6 but snowingos is secured a friction ring III- on the rear side of which is secured the hook plate 3| whose ends I! and I3 are provided with slots 34' and 35 which will freely receive the bodies 36 and 31 of the screws 38 and 39. The screws 38 and 39 are threaded into the projections 40 of the base 2|. A spring Ii-A is placed on the screw body 36 between a projection 40 and the plate ll. A spring tl-A is placed on the screw body 31 between a projection 40 and the plate ll.

Between the hook plate 3| and the base 2| is mounted the floating plate 4| through which the bodies 36 and 31 of the screws 38 and it freely pass. The floating plate ll has provided at its refer to similar parts end II is retracted, the points II and 42 separate leaving the starting windings reset for a reverse rotation.

Isnuallu actuated switch unit The manually actuated switch unit M consists of a base 44 which may be mounted on the motor or any other convenient place, and which is provided with the ends 41 and 4| between which are disposed the bars as and II of insulating material.

A cylindrical switch rotor II is also disposed between the ends 41 and 4| and is pivoted to the end 40 by means 01 the pin 52 which forms a part of the head It, which in turn is secured to the end 4| while the pin I! extends ireely into the rotor ll.

The rotor II is provided with an end slot 84 to receive the tongue I! which projects from the cylindrical head I of the rotor II and aflords a means ior rotating the rotor Si by means of the hand lever 51 which is mounted on a bushing 58 and secured to the stub shaft II by means a set screw CI.

The member I! is provided with the stops 8i g and I to limit the movements of the member II.

A spring urged pawl CI engages the cylindrical surface '4 and is contained within the guide 05. The surface 04 is provided with an intermediate notch 00 which holds the member II in an of! position.

The member II is provided with an elongated contact bar I! at one side 01' one end and a similar bar 60 at the other side of the other end thereof. The bar ll is connected to the circular contact I by means of the rivet II while the contact bar it is connected to the circular contact H by means of the rivet 12.

The rivets ll and II are shown as parts of the contacts I! and It in the diagrammatic views I and I in which the member II is illustrated as a shaft for the sake of clearness.

It will be seen in Figs. 3. and 4. that there are disposed on the bar II a plurality of adjustable spring contact arms I8, I4, II, and I. which are secured to the bar ll by means of the screws II. The arms 14 and II are tied together electrically bymeans of the bar 18. Adjusting screws 10 control the pressure of the contact points ll against the surface of the member II or the contact members I1, I, It, and Ii.

Similar arms ll, 02, ll, and "are disposed alongthebarllbutthesecontactsareallseparate. Thatis,theyarenotlinkedbyamember similartothebar ll. A cover "encloses the mechanism just described.

lnconnectingtheunitsl'andutoasplit phase motomthccontactsllanduareconnectedto thepowerlines OI and. The contact '8 is oonnectedbyaleadlitothecontsctarmfl whilethecontactllisconnectedbytheleadsl totheoootactarmfl. Thefloatingplateflis connectedbytheleadlltothestartingwinding assassv tlwhoselead Ilisconnectedtothe contacts 14 and". Thecontact 'Ilisconnectedbythelead I tothe runningwinding l2 oithe motor. The winding llisconnectedbytheleadlitotheeontact".

the rotor ll, it- !ollows that the clockwise rotation of the member 20 will, through frictional engagement with the disc 80, rotate the disc 80 and its attached arms 32 and I! in a clockwise direction, causing the slot 34 to engage the body II of the screw as latched thereon as shown in Figs. 1, 6 and 7.

It will be seen in Fig. 1 that current now flows from the line wire 95 to the contact arm Ii to the circular contact ll, across the rivet II to the bar it which engages the contact arms I! and 14. The contact I3 permits current to now through the lead II to the running winding 82 and the members I, It, I0 and 84 to the line 84, and simultaneously current flows from the contact arm I4 to the starting winding 89 to the floating plate 4|.

Now it will be remembered that the armature or rotor is is not yet in motion or up to speed, and the parts are still in a position shown in Fig. 8. That is, with the contacts 11 and 45 engaging and the contacts 28 and 44 .engaging. Therefore current can flow through the starting winding arm 35 N, the lead 30 to the line 94 causing the rotor I.

to turn in the desired direction. However, as soon as it attains speed and the counter-weight i1 is thrown outward by centrifugal force to the position shown in Fig. 6 wherein the member 2| is retracted, then the contacts It and 44 are separated. thereby interrupting the flow of current through the starting winding I! until the position of the lever 51 is reversed to that shown in Fig. 2.

A better understanding oi this device may be gained by the simple statement that during any rotation of the rotor 40, the frictional unit 1'' is set to a reversed position but does not become effective unitl the lever I! is operated manually. That is to say, it the motor is operating in a clockwise direction, it is irictionally set to have the relation between its starting and running circuits instantly reversed by a manual switch operation, through purely mechanical means and without the employment of excessive and cumbersome transformers, relays, etc., and without waiting for the rotor to come to rest before reversing action can take place.

This is especially desirable where quick reversals are desired. It will be noted also that with this arrangement, there is a definite blocking or electric braking action set up to oii'set the inertia oi the rotor and prevent excessive strain on the moving parts.

In practice, it is desirable to provide an antiv between the members II and 4| so that the memher 2| may irictionally drive the parts in the desired direction.

We are aware that numerous devices have been constructed in the past for reversing motors. We therefore do not claim such devices broadly, but we do intend to cover all such forms and modifications of this device as fall fairly within the appended claims:

We claim:

1. A motor control system for a motor having starting and running windings and a speed responsive switch operating element; including a main control switch for energizing and deenergizing the starting winding of the motor for starting and stopping the motor and a reversing switch operable with the main control switch ior operating the motor in a forward or a reverse direction, a pair of switches each normally urged to open position but closed by the speed responsive operating element of the motor when the motor is at rest, said pair of switches cooperating with the reversing switch and the main control switch for energizing the starting winding of the motor for starting the motor in either direction until the motor speed responsive switch operating element moves, and means engaged and moved by said speed responsive switch operating element during the initial movement thereof to hold one switch 01' said pair of switches from opening while permitting the other switch of said pair to open to deenergize thestarting winding aiter the motor has started, whereby movement of the control and reversing switches for a reverse energization of the starting winding for operation of the motor in the reverse direction will eilect an immediate energization of the starting winding for that purpose, even before the motor comes to a stop.

2. Reversing switch mechanism for a single phase motor including starting and running windings, and a speed responsive switch operating element; comprising a control switch for applying electrical energy to the running winding and a reversing switch operable therewith. a floating plate connected to the starting winding and having switch elements disposed at op posite ends thereof adapted to be closed and opened by the movement of said plate in response to movement of said speed responsive switch operating element, spring mearm for urging both ends of the plate in a switch opening direction, a pair of latches one latch for each end of the plate, selectively operable on one end or the other end of the plate to hold the selected end in switch closing position and allow the other end to move to open its switch to deenergize the starting winding after the motor has started so as to maintain the starting winding in readiness for a reverse energization, and means operated by the speed responsive switch operating element for shifting the latches during the initial rotary movement of the motor in either direction to properly set the latches for an instantaneous reversing of the motor by the appropriate actuation of the control and reversing switches.

3. Reversing switch mechanism for a single phase motor of the type having starting and running windings and aspeed responsive switch operating element, comprising a control switch for applying electrical energy to the running winding, a reversing switch operable therewith, a selective switch mechanism including two sets of contacts normally urged to open position, said sets of contacts being closed by the speed responsive element and in cooperation with said reversing switch operable to apply electrical energy to the starting winding for starting the motor in either direction, and means operated by the speed responsive element for opening one set of said closed contacts to open the circuit thru the starting winding and operable to maintain the other set of contacts closed during the starting of the motor in preparation for an immediate reversal of operation of the motor at any time by a subsequent appropriate actuation of the control switch and the reversing switch.

4. A frictionally set switch unit for use with a split phase motor having a shaft, a main switch unit. and a speed responsive. element; comprising a pair of relatively stationary spaced contacts, a movable plate having a contact at either end in position to engage the proximate contact of the first mentioned contacts, spring means iorurging the adjacent contacts out of engagement with each other, means movable with the speed responsive element for forcing the movable plate toward the first mentioned contacts against the urge of said spring means to cause engagement of the two sets of contacts, and latching means frictionally engaging the motor shaft to hold one or the other of the plate carried contacts, depending on the direction of rotation of the motor shaft, in engagement with its proximate contact of the first mentioned pair while the spring means holds the other plate carried contact out of engagement with its proximate contact; whereby when the spaced contacts are connected with the line and the movable plate is connected to the starting winding, the latter may be energized for reversal of the motor before the motor comes to a full stop.

, CHESTER E. SPRAGUE.

NELSON M. SPRAGUE. 

